1. Field of the Invention
The invention relates generally to the field of service indicators such as diagnostic LEDs that are used to display information regarding a component of an electrically powered device such as a computer storage system, photocopier or the like, and, more specifically, to a way of providing backup power so that the service indicator continues to be active even when power is removed from the component.
2. Description of the Related Art
Various electrically powered devices such as computer systems, storage controllers, photocopiers and many others have a diagnostic functionality to indicate when servicing or replacement of their components is needed. Diagnostic control logic may process signals from sensors and actuators of the components to determine when a component is not performing properly or otherwise requires servicing, for instance. The components may have diagnostic indicators, e.g., service aid indicators, such as LED lights, that are illuminated to convey specified information. In a simple case, the light is illuminated when the component requires attention. In other cases, a series of flashes identifies the type of attention that is needed. However, for devices that have packaging concepts that require component assemblies to be removed from a chassis and therefore an associated electrical power source, the use of the diagnostic indicators to direct maintenance actions is compromised. Typically, the electrical power at the device is disconnected from the component, e.g., when the component is removed from the device, when a component is a subassembly located within a higher level assembly that must be removed from a chassis and disassembled, or when the technician switches off the power to the component for safety reasons, e.g., to avoid being shocked while working on the component.
For example, during field maintenance of such devices, a directed service action is typically performed, where the device has identified and isolated a failure to a component within a subassembly that cannot be seen by the technician while the subassembly is installed within the higher order assembly. The service action may include servicing, including repair or cleaning, or replacement of a component, for instance. The technician may therefore require access to components internal to a sub-assembly to continue the maintenance activity. For instance, when a memory module is being serviced within a computer chassis, a common practice is for the technician to remove power to the computer chassis prior to disassembly. Once power has been removed from the chassis, service/diagnostic indicators that are powered from the chassis power source no longer have power. Once the chassis is opened, the technician wants to identify which component is being identified, by its diagnostic indicator, for servicing or replacement.
In such situations, when the diagnostic indicator is no longer powered, it cannot aid the technician at a time when it is most needed.